Re: please advise: Mustek 12000SP, NCR810 & color stripes

From: FJA van Zijp (ferencj@xs4all.nl)
Date: Sun Jan 21 2001 - 13:46:56 PST

  • Next message: Henning Meier-Geinitz: "Re: please advise: Mustek 12000SP, NCR810 & color stripes"

    Hi,

    Well, whaddayaknow. It works. I wrote I connected the Mustek to a
    noname NCR810 card, but actually it was connected to my Asus
    SC200 SCSI card. Ah well, shouldn't matter, thinks me.

    But it turns out it does matter. The scanner now IS connected
    (solely) to the noname NCR810 card, the rest (ZIP and CDROM) is
    on the SC200. No more colored stripes.

    I'm still curious. Anybody ANY idea what was going on?

    > > I've read somewhere (in SANE docs?) that this Mustek should be
    > > terminated (by me). But my active terminator makes the line
    > > phenomena a lot worse. What is it with this scanner? Doesn't it
    > > follow SCSI specs, or has it auto-termination?
    > I wouldn't trust scanners to follow SCSI specs, specially if they come
    > as a package with SCSI card etc. My acer caused problems with other
    > devices on the same chain until I removed from the PCB a bunch of capacitors
    > they had put on the SCSI signal lines. They either put them on for EMI or
    > an attempt to sort of terminate but caused too much reflection when you
    > had other devices on the chain which were using faster data rates.

    I've got an old SONY-cdrom with similar thingies to what you
    describe. I'm quite sure they're for passive termination. If I
    remember clearly, passive termination consists of resistors of a
    certain Ohm, active termination actually keeps a certain voltage on
    the signal lines (with thyristors?.)

    cheers

    Ferenc

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